This post shares a quick tip about how to choose the right silicone mold for your epoxy resin casting project. Do you need a shiny or matte resin silicone mold, and what’s the difference?
Are silicone molds good for resin casting?
Silicone molds are an excellent choice to cast epoxy resin in because silicone is great at producing excellent detail, is flexible, and is durable. And, most importantly, epoxy resin won’t stick to it!
Silicone resin molds are also not one-and-done purchases. You can use them over and over again. You can even make your own! But beware that different types of silicone can wear down faster, tear, or begin sticking to your resin after it cures. For example, food-safe silicone. Think candy molds and whatnot.
On that note, keep in mind that not all silicone molds are food-safe. The only type of silicone that is food-safe is platinum-cure silicone, as noted by the U.S. Food and Drug Administration. These tend to be a bit more expensive than other silicone molds, but they still aren’t terribly expensive.
Shiny or matte resin silicone mold: What’s the difference?
But there isn’t just one type of silicone mold. Today I am sharing a quick tip about the difference between shiny and matte resin silicone molds. Because not knowing that different recently caused me a lot of frustration, on a specific project, and I couldn’t find any info on it!
Now that I know the reason, however, it seems like a total no-brainer: the epoxy resin takes on the sheen of whatever the mold’s finish is. That means that even though resin has an extremely high-gloss sheen when cured, it can look dull and even a bit bumping when cast into a matte mold. Here is an example of a matte mold I ordered online (not knowing its finish) and the result.
Matte silicone plant pot mold example
See how dull it looks compared to the super shiny side—the bottom of the planter—that had no contact with the mold? The difference is massive! At first I thought it might be the mica pigmentation dyes I was using, but after a lot of trial and error, I realized it was the damn mold.
I hate wasting things. So even though I bought this for resin casting, that was a fail. I ended up using it with concrete, which was perfect! The concrete planters cast from this matte silicone mold are beautiful. Note that I don’t think matte vs. shiny molds is a consideration for concrete, only resin.
Shiny silicone plant pot mold example
I ordered these new molds that seemed to have a shinier look online. Luckily the photos were pretty accurate, and when they arrived, I knew they’d be a better fit for my project. The inside of the mold was much smoother and shinier. See what a difference it makes?
So if you’re furiously googling “why does my resin look dull after casting it in a silicone mold,” I hope you land here and I can help you out.